Unformatted text preview: f a particular type. If a process has a pending signal of type , then any subsequent signals of type sent to that process are not queued; they are simply discarded. A process can selectively block the receipt of certain signals. When a signal is blocked, it can be delivered, but the resulting pending signal will not be received until the process unblocks the signal. A pending signal is received at most once. For each process, the kernel maintains the set of pending signals in the pending bit vector, and the set of blocked signals in the blocked bit vector. The kernel sets bit in pending whenever a signal of type is delivered and clears bit in pending whenever a signal of type is received. 8.5.2 Sending Signals
Unix systems provide a number of mechanisms for sending signals to processes. All of the mechanisms rely on the notion of a process group. Process Groups
Every process belongs to exactly one process group, which is identiﬁed by a positive integer process group ID. The getpgrp function returns t...
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